King appeals to the emotions of the clergymen to whom he addressed his letter in many places throughout the letter.
His opening paragraph recognizes the role of his audience as leaders of their congregations and their communities, individuals whose reasoned reactions were of importance to him. "I feel that you are men of genuine good will and that your criticisms are sincerely set forth..."
He cites the past history of blacks in the United States and of previous efforts to obtain civil rights, appealing to the lack of progress and sense of frustration resulting from repeated delays and denials and excuses.
...last September, came the opportunity to talk with leaders of Birmingham's economic community...certain promises were made by the merchants--for example, to remove the stores' humiliating racial signs. On the basis of these promises,...the Alabama Christian Movement for Human Rights agreed to a moratorium on all demonstrations. As the weeks and months went by, we realized that we were the victims of a broken promise...We had no alternative except to prepare for direct action...We decided to schedule our direct action program for the Easter season, realizing that except for Christmas, this is the main shopping period of the year.
He reminds them of the personal tragedies that had been endured by participants in the civil rights movement and reminds them of the need to recognize the justification of action.
Perhaps it is easy for those who have never felt the stinging darts of segregation to say, "Wait." But when you have seen vicious mobs lynch your mothers and fathers at will and drown your sisters and brothers at whim; when you have seen hate filled policemen curse, kick and even kill your black brothers and sisters...then you will understand why we find it difficult to wait.
He appeals to the clergymen as representatives of the larger church, a body that he felt was failing to uphold its central responsibility of fighting to support the oppressed and correct the wrongs inflicted upon the powerless.
There was a time when the church was very powerful--in the time when the early Christians rejoiced at being deemed worthy to suffer for what they believed...Things are different now. So often the contemporary church is a weak, ineffectual voice with an uncertain sound...But the judgment of God is upon the church as never before. If today's church does not recapture the sacrificial spirit of the early church, it will lose its authenticity, forfeit the loyalty of millions, and be dismissed as an irrelevant social club with no meaning for the twentieth century.
In closing, he indirectly appeals to their sense of sympathy and empathy for a fellow clergyman in a hard situation.
Never before have I written so long a letter. I'm afraid it is much too long to take your precious time. I can assure you that it would have been much shorter if I had been writing from a comfortable desk, but what else can one do when he is alone in a narrow jail cell, other than write long letters, think long thoughts and pray long prayers?